RNR3

RNR3 is an acronym most commonly associated with a ribonucleotide reductase subunit gene in the budding yeast Saccharomyces cerevisiae. RNR3 is a paralog of the ribonucleotide reductase small-subunit genes and contributes to the enzyme complex that reduces ribonucleotides to deoxyribonucleotides, the building blocks of DNA. Ribonucleotide reductase is a rate-limiting enzyme in dNTP synthesis and plays a central role in DNA replication and repair, helping maintain genome stability during cell division and stress.

Expression and regulation: RNR3 expression is typically induced under conditions of DNA damage and replication stress. It is part of the inducible response that augments intracellular dNTP pools when DNA integrity is challenged. In contrast to the core, constitutively expressed subunits, RNR3's activity is condition-dependent. Functional studies in yeast indicate that RNR3 is not strictly essential for viability under normal growth, but its presence improves survival or tolerance to DNA-damaging treatments in laboratory settings.

Distribution and context: Within Saccharomyces cerevisiae and some related fungi, RNR3 exists as one of several RNR-related genes; its genetic organization and regulatory controls can vary among species. The term is most precise within fungal genetics, and homologous genes may have diverged functions in other lineages.

Other uses: In non-biological contexts, RNR3 may be used as an acronym for unrelated terms or product identifiers, but this article focuses on the gene context in yeast.